Polyazo dyestuffs and the metal complex compounds



United States Patent POLYAZO DYESTUFFS AND THE METAL COMPLEX COMPOUNDS Ernst Iselin, Dornach, and Walter Wehrli, Riehen, Switzerland, assignors, by mesne assignments, to Saul & Co., Newark, N. J., as nominee of Fidelity Union Trust Company, executive trustee under Sandoz Trust No Drawing. Application July 15, 1955 Serial No. 522,376

Claims priority, application Switzerland July 16, 1954 6 Claims. (Cl. 260-145) The present invention relates to polyazo dyestufls and to metal complex compounds thereof.

The polyazo dyestufis of the present invention can be obtained by coupling (a) one mole of the diazo compound of an aminodisazo dyestutt which corresponds to the formula no (II) or with a metal complex compound thereof, wherein y represents an alkyl, cycloalkyl, aralkyl or aryl group, which may be further substituted, and z represents an hydroxy or carboxylic acid group, and wherein the nu cleus A may bear additional substituents such as are usual in azo dyestufis. The metal complex compounds of the present invention can be obtained by treating the thusprepared polyazo dyestuffs in substance or on the fiber with a metal-yielding agent.

The new polyazo dyestuffs of the present invention correspond, in the metal-free state, to the formula H038 I NH-11 E (III) wherein x, y, z, R R R and A have the afore-recited significances. These new dyestufis are excellently suited .for the dyeing of cotton and fibers of regenerated cellulose in gray shades. The dyeings obtained directly with the metal complex compounds or with the polyazo dyestulfs metallized on the fiber according to a single bath copper-ing process or an after-coppering process, are characterized by very good fastness to light and to washing.

As indicated, R R and R as well as nucleus A may bear further substituents such as are usual in azo dyestuffs. Such substituents are, for example, halogen atoms (e. g. fluorine, chlorine, bromine), low molecular alkyl groups (e. g. methyl, ethyl), low molecular alkoxy groups (e. g. methoxy, ethoxy), acylamino groups (e. g. acetylamino, propionylamino, benzoylamino, carbomethoxy amino, carbethoxyamino), the hydroxyl group, the carboxylic acid group, the sulfonic acid group, sulfonic acid amide groups which may be substituted at the nitrogen atom (e. SO2.NH2, -SO2{N(CH3)2, -SO .NH.C H SO NH.C H OH,

, and low molecular alkylsulfonyl groups (e. g. SO2.CH3)

The radical y may, when it is an alkyl group, advantageously be substituted by an hydroxy or methoxy group, and when it is an aryl group, its substituents may also comprise the amino group or an aryl radical; thus for example, the (2-hydroxy)-ethyl-, the (3'-methoxy)-propyl-, the (4'-amino)-phenyland the (4"-amino)-1,1"- diphenyl-radicals are excellently suitable to occupy the position of the symbol y in Formulas II and. III.

It is essential that the radicals R R R and y and nucleus A together contain the number of water-solubilizing groups necessary to impart water-solubility to the final products.

The aminodisazo dyestuffs of Formula I, which serve for the preparation of the diazo compounds, can be obtained in per se known manner, for example by diazotizing the initial component R --NH wherein R; has the precedingly-recited significance, coupling the resultant diazo compound in weakly acid medium with a middle component R NH' wherein R also has the previouslyrecited significance, further diazotizing the obtained amino-monoazo compound and coupling the resultant diazo compound in weakly acid medium with component xR -NH wherein R and x have the previously-recited significances.

The aminoazo compounds of Formula II are obtained by the coupling, in acid medium, of diasotized Z-aminol-hydroxybenzenes and Z-aminobenzene-l-carboxylic acids with the Z-amino-S-hydroxynaphthalene-7-sulfonic acids substituted at the nitrogen atom. By metallization of the thus-obtained coupling products there are obtained the corresponding metal complex compounds.

The diazo compounds of the aminodisazo dyestuiis I are coupled with the aminoazo compounds II or the corresponding metal complex compounds in alkaline medium, advantageously in a solution which is alkaline with ammonia or with bicarbonate and in the presence of a compound Which has an accelerating action on the coupling reaction, for example, a tertiary organic base such as pyridinefquinoline, or a' technical pyridine base mixture; The thus-prepared-polyazo dyestuffs can be precipitated from the coupling mass by the addition of acid or by the additionof sodium chloride. The precipitates can, after filtration, be advantageously purified by re-dissolution in water, salting out and again filtering off. The so-obtained polyazo dyestuffs, which correspond to Formula III, supra, are well soluble in water and yield a specific solution coloration in sulfuric acid.

Conversion of the metal-free polyazo dyestuffs or the polyazo dyestuffs COntaining l metal atom into their complex compounds containing 2 metal atoms can be effected according to per se known metallizingprocesses,- advantageously by heating the dyestuffs in aqueous solution or suspension with ametal-yielding agent in the presence of alkali salts of low molecular aliphatic monocarboxylic acids or by heating the aqueous dyestufi solutions with complex metal salt solutions. The metallization must be carried out under conditions which assure the splitting of the alkoxy group x. The metal involved in the metallization is preferably copper.

l SOaH The following examples set forth representative embodiments of the invention, but are not at all intended to be limitative of the latter. In such examples, the parts and percentages are by weight and the temperatures are in degrees Centigrade.

Example 1 55.5 parts of the aminodisazo compoundobtained by coupling diazotized 1-aminobenzene-3-sulfonic acid with 1-aminonaphthalene-7-sulfonic acid, further diazotizing the aminomonoazo compound, and coupling the resultant diazo compound with 2-amino-1-methoxy-4 methylbenzene-are stirred into 500 parts of water. 7 parts of sodium nitrite are added to the resultant suspension which is then rendered acidto Congo red by the ad.- dition of 50 parts of concentrated hydrochloric acid at 10 while stirring thoroughly. At the end of 2 or 3 hours, the diazotization is over. The obtained diazo suspension is then added, with ice cooling, to a solution of 51.6 parts of the monoazo compound obtained by the acid coupling of diazotized Z-amino-l-hydroxybenzenelsulfonic acid amide with Z-phenylarnino-5-hydroxynaphthalene-7-sulfonic acid, 400 parts of water, 400 parts of pyridine and parts of concentrated aqueous ammonia. Coupling to the tetrakisazo dyestuff ensues forthwith; it is over in a short time. The coupling mass is then rendered weakly acid with concentrated hydrochloric acid and the dyestufi which precipitates is filtered off. The obtained filter cake is stirred into 1000 parts of water and the obtained suspension is rendered weakly alkaline by the addition of aqueous caustic soda solution, whereupon the dyestuff dissolves. It is then salted out, filtered oif and dried. The so-obtained new tetrakisazo dyestuficorresponds to the formula 4 and is a a dark powder which dissolves in water to yield a reddish blue coloration and in concentrated sulfuric acid to yield a gray-blue coloration, and dyes cotton and fibers of regenerated cellulose by a single bath or twobath coppering process in pretty gray-blue shades of very good fastness to light and to washing.

To convert the tetrakisazo dyestutf into the copper complex compound, the moist filter paste is dissolved in 1500 parts of water at There is then added to the solution a mixture of 50 parts of crystalline copper sulfate, 200 parts of water and 90 parts of concentrated aqueous ammonia solution and then the entire mixture is boiled under reflux until the methoxy group has been) split. This operation requires about 6 to 12 hours. The resultant copper-containing tetrakisazo dyestufi is salted out, filtered off and dried. It corresponds to the formula and is a dark powder which dissolves in water and in concentrated sulfuric acid to yield a gray-blue coloration, and dyes cotton and fibers of regenerated cellulose in gray shades of very good fastness to light and to washing.

Example 2 65.4 parts of the aminodisazo compound0btained by coupling diazotized 1-amino-4-hydr0xybenzene-3-car boxylic acid with 1-arninonaphthalene-7-sulfonic acid, further diazotizing the aminornonoazo compound and coupling the so-obtained diaz'o compound with l-arnino; 2-rnethoxyriaphthalene-6-sulfonic acidare stirred at 60 into 500 parts of water. 7 parts of sodium nitrate are then added to the resultant solution which is thereupon cooled to 10-15" and poured into a mixture of 50 parts of concentrated hydrochloric acid and 200 parts of ice. The reaction mass is stirred for 2 to 4 hours, while cooling with ice. Upon conclusion of the diazotization, the precipitated diazo compound is filtered off and is then introduced, in the form of concentrated moist paste, into an ice-cooled solution of 51.4 parts of the monoazo compound obtained by acid coupling of diazotized Z-amino- 1-hydroxybenZene-4-su.lfonic acid amide with 2-phenylamino-5-hydroxynaphthalene-7-sulfonic acid, 400 parts of water, 600 parts of pyridine and 25 parts of sodium bicarbonate. Coupling to the tetrakisazo dyestuff ensues forthwith. The coupling is finished at the end of 4 hours. The coupling mass is then rendered weakly acid to Congo red by the addition of hydrochloric acid, the precipitated dyestuff is filtered oif and the filter cake is again stirred into 1000 parts of water. The resultant suspension is rendered weakly alkaline by means of aqueous caustic soda solution, whereupon the thus-redis- 6 solved dyestutr is again salted out, filtered ofl. anddried. and which yields dyeings of very good fastness to light. It corresponds to the formula and washing on cotton and fibers of regenerated cellulose,

| no. HOQN= N=N N=N 0011 on. H

Os-NHI and is a black powder which dissolves in water to yield both as the after-coppering dyestuff and as the copper a blue-green coloration and in concentrated sulfuric acid complex compoun o i to yield a blue-gray coloration and dyes cotton and fibers of regenerated cellulose by an after-coppering Example 4 process in neutral gray shades of very good fastness to light and to washing, 60.5 parts of the aminodisazo compound-obtained Conversion of the dyestufi into the copper complex by coupling diazotized 2-aminonaphthalene-4,8-disulfonic compound is effected y dissolving the moist filter Paste acid with l-aminonaphthalene, further diazotizing the gig i2 535 52212223; igl pzggg g ggigil gq aminomonoazo compound and coupling the so-obt ained stuff after the manner described in the preceding example, dlazo g g 2 552 z zggg g gg g and then working up the product as there set forth. The m 0 par 5 p copper containing tetrakisazo dyesmfi thus prepared sodium nitrite are added to the resultant suspension which responds to the formula is then introduced into a mixture of 25 parts of concen- SOPNH:

and is a dark powder which dissolves in water and in trated hydrochloric acid and 250 parts of ice. The reconcentrated sulfuric acid to yield a g y coloration and sultant reaction mass is stirred for 2th 3 hours at 0-5, at y cotton and fibers of regenerated Cellulose neutral the end of which time the diazotization is finfiished. The gray Shades of hlgh fastness to hght and t0 washmg' resultant diazo compound is then introduced, while cool- Example 3 ing with ice, into a solution of 54.6 parts of the monoazo Upon replacing the 51.4 parts of the monoazo comcompound Obtained y the acid coupling of diaZOfiZed pound used in the preceding example by 51 .3 parts of 2-amino-1-hydroxybenzene-4-sulfonic acid amide with the monoazo compound prepared by the acid couphng 55 z (4r methoxy) pheny1amino 5 hydroxynaphthalene 7 of dlazoilzed z'ammo '1.'hydmxy'4'methylsulfonylbensulfonic acid, 50 parts of sodium bicarbonate, 600 parts zene with Z-phenylamrno-5-hydroxynaphthalene-7-sulf d 600 ts f U on com letion fonic acid, asimilar tetrakisazo dyestutf is obtained which 0 water P PY 1118: P P 0 corresponds to the formula of the couplmg, the coupling mass is heated to -80 (IIH oorr on.

i'esult'aii't"tetraki'sazo dyestuE- 'vvhich corresponds to and 100'pa'rts'ofs'odiurn chloride are then added, and the arerauma reaction mass is cooled to 5 to by the addition of 'ice.

1?: v B Or-N a :11 on; no-,s- NHOO CH1! N= N=NON=N- )CH3 HO is precipitated by the addition of sodium chloride, and The resultant suspension is then run into a mixture of is thenfilt ered'ofiand dried. It 18 a blacl c'powder which '20 75 parts of concentratedhydrochloric acid, 200 parts of dissolves in Water to yield a blue coloratl'on and in coni d im f water, h mass is stirred 5= centrated lf and to y e a blue-gray coloratlomuntil the .diazotization which ensues isended, which will and dyes com)? and fibers, of regenerated cellulose by he the case after about 4 to 8 hours. The precipitated an eg QPPW E fi i l gray shades of very diazo compound is then filtered ofi and is introduced in the 'co' 'er coin lx com oundfthemoist filter aste is dissolv e' d in 200% partsoi water at 85-90 with zi dditio'n by P of-30 parts of sodiumcarbonate, and-is then coPpered l "acld 'v'amllde Yvlth Lphenylammwfihydmxy' after the manner Setforth in Example The Obtained naphthaleneJ-sulfonicacid, '400-parts of water,-400'parts cq pcr-containing tetrakisazo dyestuff corresponds to the techfiic'l Pyridine ibase'mixmre and Parts of formula eentratedaqueous ammonia solution. The'ensuing cou- SIOr-NHI ,7 S0311 (13H; HOa'S- N--Cu-O .N=N N=NQIYI=NM I o -u--o OCH:

and is adark powderwhich"dissolvesin waterand inconpling--to the tetrakisazo dyestufi'is concluded in a short centrated sulfuric acid to yield a gray coloration and time; :t-he dyestuffwsolutiomis acidified With concentrated dyes cotton and fibers of regenerated cellulose in new hydrochloric acid to separate the pyridine bases, after tral gray shades of high fastness to light and to washing. 50 which-tl1e :dyestuff: is filtered off, recrystallized once or v twice from dilute aqueous caustic soda solution and finally Example 5 salted out of solution, filtered on and dried. The ob- 62.1parts' oftheaminodisazo compound obtainedby tained tetrakisazo dyestuffcorresponds'to the formula coupling diazotized 1-aminonaphthalene-S-sulfonic acid, andfisadark powder which dissolves in water to yield a with 1-aminonaphthalene-7-sulfonic acid, further diazoblue coloration and in concentrated sulfuric acidto yield tizing the obtained aminomonoazo compound and coua blue-gray coloration, and dyes cotton-@andsfibers of re-:

pling the resultant diazo compound with 2-amino-1,4- generated cellulose by a single bath or a two-bath copperdimethoxybenzene-are dissolved in 900 parts of water ing p'roce'sshin pretty gray-blue shades of veryhigh fastat 60 with the addition of 50 parts of concentrated ness to light and to Washing.

aqueous caustic soda solution. 7 parts of sodium nitrite Conversion of the tetrakisazo dyestuff into the copper 9 complex compound takes place after the manner described in Example 1. kisazo dyestufi corresponds to the formula I HOsS no. d--du and is a dark powder which dissolves in water and in concentrated sulfuric acid with gray coloration, and dyes cotton and fibers of regenerated cellulose in neutral gray shades of outstanding fastness to light and to washing.

Example 6 The resultant copper-containing tetra of regenerated cellulose, by an after-coppering process or also in the form of the copper compound containing 2 copper atoms.

The following table sets forth additional polyazo dyestuffs which can be prepared after the manner of the foregoing examples. These polyazo dyestuffs all correspond in the metal-free form to the Formula III. Col- 20 umn 2 of the table sets forth the aminobenzenes and aminonaphthalenes from which the diazo components R are prepared, columns 3 and 4 set forth the aminobenzenes and aminonaphthalenes corresponding to the middle components R and x-R and column 5 sets forth the 25 end components obtained by acid coupling of a diazotized Z-amino-l-hydroxybenzene or a 'diazotized Z-aminobenzene-l-carboxylic acid (a) with a Z-amino-S-hydroxynaphthalene-7-sulfonic acid (b), or the copper complex Hogsis obtained. This dyestutf yields gray dyeings of very high fastness to light and to washing on cotton and fibers SOsH compounds thereof. Column 6, finally, shade of the coppereddyeings on cotton.

indicates the i 1 4 2 amino-l-hydroxy- 2 amino-5-hydroxy- Ex- Diazo Components Middle Components Middle Components benzene or Z-amiuonaphthalene-7 sul- Dyeing ample (corresponding to 3;) (corresponding to R2) (corresponding to R benzene 1 cerboxionic acid on NO.- ylic acid cotton x r (a) 7 1-amino-4-hydroxyl-aminonaphthalene-fi- 2-amin0-1-methoxy-4- Lamino-Z-hydroxy-Ei- 2-(4-chl0ro)-phenylgray. benzene-B-carboxsulfonic acid. methylbenzene. carboxybenzene-5- amino-5-hydroxyylic acid. sulfonic acid. naphthalene-7- sulfonic acid. 1 8 1-amino-4-hydroxy-3- l-aminonaphthaleneaamino-l-methoxy-i- 2-arnino-1-hydroxy- 2-phenylamino-5-hy- Do.

carboxybenzene-5- 7-sulfonic acid. ethoxybenzene. benzene-4-su1fonic droxynaphthalenesulfonic acid. acid-methylamide. 7-sulfonic acid. 9 d0 l-aminonaphthalene 2-aznino-Lmethoxy-4- Z-amino-l-hydroxy- 2-(4-carboxy)-pheny1- Do.

. methylbenzene. benzene-at-sulfonic amino-.S-hydroxyacid-(2-hydroxy)- naphthalene-7- i r ethylamide. sulfonic acid. .10 1-amino-2-hydroxy-3- l-aminonaphthalenedo 2 emino-1-hydroxy-4- 2-phenylamino-5- Do. carboxybenzeue-o- G-sulfonic acid. methylsulfonylhydroxynaphtha i suli'onic acid. benzene. 1e11e-7-su1fonic acid. 11 do .-d0 do 2-amino-1-hydroxy-4- 2-(8-carboxy)-phenyl- Do.

nitrohenzene. amino-5-hydroxyr naphthalene-7'- sulionic acid. 12 1-azninobenzene-4- -...d0-; do Zamino-l-hydroxy-4- 2-(4-methy1)-pheny1- r v sulfonlc acid. f p i chlorobenzene. amino-fi-hydroxynaphthalene-7,3-

disulfonic acid. 13 Z-aminonaphthalene- 1-amino-3-methy1ben- -d0 2-amino-1-hydroxy-4- 2-phenylamino-5- Do. 6,8-disulfonic acid. zene. chloro-6-nitrobenhydroxynaphthazene. leng-7,4-disulfonic r acl 14 l-aminonaphthalenel-aminonaphthalenedo Z-aminn-l-hydroxy- 2-pheny1amino-5- Do. 4su1fonic acid. 7-sulfonic acid. benzene-5-su1fonic hydroxynaphtha- I acid. lene-7-su1ionic acid. 15 l-aminonaphthalenel-aminonaphthalene- 2-amino-1,4diethoxy- Z-amino-l-hydroxy- -do Do.

8-su1fonic acid. 6-sullonic acid. benzene. benzene i-sulfonic I acid-(3-methoxy)- I propylarnide. 16 l-aminonaphthalene- 1-aminonaphtha1ene 1-amino-2-ethoxy Z-amino-l-hydroxydo Do.

3,8-disulfonic acid. naphthalene fibenzene-4-su1fon1c r sulfonic acid. acicilcyclohexylam e. 17 2-aminonaphtl1a1ene- ...do 2-amlno-L4-dimeth- Z-amirio-l-hydroxy- -do Do.

3,6-dlsulfonic acid. oxybenzene. benzeneA-sulfonic acid-phenylamide.

, 2 amino-Lhydroxy- 2 amino-S-hydroxy- Ex- Diazo Components Middle Gomponents Middle Components benzene or Z-aminonaphthalene-7 sul- Dyeing ample (corresponding to R1) (corresponding to R1) "(corresponding to Rs) benzene 1 carboxionic acid on No. ylic acid cotton 18 Z-aminonaphthalene- 1-aminonaphthalene. Z amino-LmethOxyA- 2-amino-1-hydroxy- 2 phenylaniino-5 by Do.

5,7-disulfonic acid. metliyibenzene. benzene-'i-sulionic droxyn'aphthaleneacid-benzylamide. 7-sulfonic acid. 19 2-aminonaphthalenedo do 2-amino-1-hydroxy- 2-methylamino-5- Do. 6,8-disulionic acid. benzene-*i-sulfonic hydroxynaphtha- 7 acid amide. lene-7-sulfonic acid. 20 1-aminobenzene-3- l-aminonaphthalenel-a'mino-2-methoxy- 2-amino-1-hydroxy- 2-cyclohexylamino-5- Do.

sulfonic acid. (i-sulfonic acid. naphthalene-G- benzene-fi-sulfonic hydroxynaphtha- 'sulfonic acid. acid-ethylamide. lene-7-sulfonic acid. 21 1-amino-4-hydroxydo do do 2-benzylamino-5- Do. benzene-3-carboxhydroxynaphthaylic acid. lene-7-sulfon1c acid.

22 -do do 'do ?ramino-l-hydroxy- 2-phenylamiuo-5- D0.

benzene-fi-sulfonic hydroxynaphtha acid-morpholide. 1ene-7-su1fonic acid.

23 1-amiu0bcnzene-3- l-aminonaphthalene- 2-amino-1-methoxy-4- copper complex compound from (2;amino -1- bluish sulfonic acid. 7-sulfonic acid. methylbcnzene. hydroxybenzenei-sulfonic acid amide (acid) gray.

-) 2-phenylamino-5-hydroxynaphthalene-7- sulfonic acid). 24 l-aminonaphthalenedo 2-amino-1,4-di1nethcopper complex compound from (2-arnino-1- Do.

' 5-sulfonic acid. oxybenzene. 'hydroxy-4-methyl-sulfonylbenzene (acid)' 2- phenylamino 5 hydroxynaphthalene 7 sulfonic acid).

Example 25 Having thus disclosed the invention what is claimed 100 parts of cotton are wetted in a dyebath containing 3000 parts of lime-free water at 50. A concentrated aqueous solution of 1 part of the tetrakisazo dyestufi obtained according to Example 1, paragraph 1, is then added to the bath, which is thereupon heated to boiling in the course of minutes and maintained at boiling temperature for 15 minutes. In the course of the dyeing process, 20 to parts of Glaubers salt are added in the form of a concentrated aqueous solution. Upon conclusionof the dyeing process, the dyed'material is allowed to cool to in the bath in the course-of 1S" to'20 'minutes, after which'it is rinsed and subjectedto an aftertreatment with copper sulfate or with a cation-active copper complex compound which preferablyis basic.

Example 26 1 part of the copper-containing tetrakisazoduestuff obtained according to Example 1, paragraph 2, is dissolved in 3000 parts of hot water. '100 parts of cotton skein or cotton material are entered into the resultant gray-blue colored dyebath at 50, and then the bath is heated to 95-100" in the course of 3O minutes and the dyeing continued for 30 morev minutes at approximately boiling temperature. In the course of the dyeing process, 20 to 4-0 parts of Glaubers salt are added little by little. After coolingto about 50, the dyed material is withdrawn from the bath, rinsed with cold water and dried. There is obtained a gray dye with excellent fastness to washing and to light.

An aftertreatment of the dyeing with copper salts, particularly in combination with cation-active compounds, may result in further improvement of the fastness properties.

1. A member selected from the group consisting of thepolyazo dyestuifs which correspond to the formula at and the complex copper compounds thereof, wherein each of R R and R is a radical selected from the group consisting of radicals of the benzene and naphthalene series, x is an alkoxy group with 1 to 2 carbon atoms, y represents amem'ber s'elec'tedfro'm'the group consisting of lower alkyl, cyclohexyl, benzyl and mononuclear aryl, z is a member selected from the group consisting of OH and COOH, and the nucleus A contains at least one substituent selected from the group consisting of C1, NO "-COOH, -SO H, -SO CH SO NH SONH.lower alkyl, SO NH.lower alkoxyalkyl, 'SOQNHlowcr hydroxy- SO NH.mononuclear aryl, SO NH.benzyl and the adjacent N=N-- are in para-position with respect'to each other, 'tlie"- N="N' groups attached to R are in para-position with respect to each other, and x is ortho-positioned 'with'respect to the N=N group bridging R and the adjacent naphthalene nucleus.

2. The polyazo dyestuff which corresponds to the formula 3. The polyazo dyestuif which corresponds to the formula aim-NH,

SO H N=N noas- N-cu-0 HOQ-N: N=N I;I=N I I 00H 0 -ou---0 80311 4. The polyazo dyestuff which corresponds to the formula SIOZNH1 N=N- 803K (3113 HO3S- N-Cu- ..N=N N=NQN=N I I O('Ju (I) 00113 5. The polyazo dyestufl which corresponds to the formula sorNm 30113 H0aS- -N- GuO l Ems )('Ju-- $0311 6. The polyazo dyestufi which corresponds to the formula SOr-NH! OCH; HOaS Nil-O References Cited in the file of this patent UNITED STATES PATENTS 2,270,675 Stein et al. Jan. 20, 1942 2,459,913 Bossard Jan. 25, 1949 FOREIGN PATENTS 639,866 Great Britain July 5, 1950 

1. A MEMBER SELECTED FROM THE GROUP CONSISTING OF THE POLYAZO DYESTUFFS WHICH CORRESPOND TO THE FORMULA 